Drilling machines



Aug. 19, 1958 H. ALLEMANN DRILLING MACHINES 3 Sheets-Sheet 2 Filed March22, 1954 Int eaten HUGO HLLEMANP/ Aug. 19, 1958 H. ALLEMANN 2,847,881

DRILLING MACHINES Fil ed March 22, 1954 s Sheets-Sheet 3 A L'Q (F -F7l-slueo ALLA-MANN United States. Patent DRILLING MACHINES Hugo Allemann,Luterbach, Solothurn, Switzerland Application March 22, 1954, Serial No.417,784 Claims priority, application Switzerland March 30, 1953 4Claims. (Cl. 77-55) This invention relates to a guide device fordrilling machines for aligning the tool and the workpiece in relation toone another in the drilling and counter-sinking of workpieces.

This device is intended to be used in place of the hitherto customarycentre punching of the workpiece. The centre punch has the object ofproviding a guide for the point of the drill, since it is practicallyimpossible to guide the drill mechanically or by hand accurately at adetermined point. Any drill will slip if its point is not guided. Thedrill can as a rule be guided manually or mechanically on to the centrepunch mark with an accuracy of a few hundredths of a millimetre, but notaccurately into the centre. The exact guiding is then taken over by thecentre punch. Particularly in the case of small holes, such as are usedin the clock industry, for example, the centre punching neverthelessupsets and bends the material of the workpiece, that is to say damagesit, thus considerably increasing the difficulty of subsequentmanufacture.

The present invention aims at obviating these difiiculties and to thisend, consists in a device for drilling machines for aligning the tooland workpiece characterised in that of the two parts to be aligned inrelation to one another, namely the tool and the workpiece, and whichare axially movable in relation to one another, one is guided radiallymovably in relation to the axis of the drilling, while the other ismounted to be immovable, and on both parts co-acting guide means are sodisposed that through the co-operation of the guide means of the movableand fixed parts, on the axial movement of the same in relation to oneanother, the tool is aligned with respect to a predetermined point onthe workpiece and the tool and workpiece are joined in such a manner asto be immovable in relation to one another.

In order that the invention may be more readily under stood, referenceis made to the accompanying drawings, which illustrate diagrammaticallyand by way of example, several embodiments thereof, and in which:

Figure 1 is a vertical section through a drilling machine in thedirection of the axis of the spindle, only parts necessary for theunderstanding of the invention being shown;

Figure 2 is a horizontal section on the line AA of Figure 1;

Figure 3 is a horizontal section of a modified embodiment on the lineB-B of Figure 4;

Figure 4 is a vertical section on the line DD of Figure 3;

Figure 5 is a modification for drilling with drilling bushes, invertical section on the line F-F of Figure 6;

Figure 6 is a horizontal section on the line E'-E in Figure 5;

Figure 7 is another modification in vertical section on the line MM ofFigure 8; and

Figure 8 is a horizontal section on the line HH of Figure 7.

In Figure 1, 1 denotes the machine frame, in which a rotating sleeve 2with a head 2 is mounted at 1 the ice sleeve having an internal bore ofsquare cross section extending longitudinally over its entire length.The sleeve 2 is held at the top by an adjusting ring 3, and is rotatedby means not shown. The working spindle 4 is provided at its top endwith a square 4 which has a small clearance 'in the internal square inthe sleeve 2 and has rounded edges in order that the working spindle 4can perform a limited deflection in any direction. An adjusting nut 5 isscrewed on a screw thread 4 on the working spindle and serves as a stopto receive the axial pressure against the sleeve 2 and for thelongitudinal adjustment of the working spindle. The working spindle 4 isguided in a bush 6 inserted in a bore in the machine frame 1, four guidepins 7 being carried by said bush. A bush 8, which is inserted in thebore 1 has at its upper end four slots or groove 8 set at an angle of toone another and V-shaped at the bottom. The four guide pins 7 restthrough the weight of the bush 6 in these grooves 8 so that the bush 6always automatically slips back into its starting position. However, assoon as the bush 6 is displaced upwardly in the axial direction, untilthe guide pins 7 bear against a ring 10 loaded by a compression spring9, the ring 10 is raised axially and the compression spring 9compressed.

At the bottom end the bush 6 has a flange-like plate 6 This plate 6 canbe made integral with the bush 6, or can be fastened on the latter as aseparate part. The guide and connecting means between the plate 6 andthe workpiece 12 can be in the form of locating pins, form guides, orboth together. The plate 6 alone determines, starting from the startingpoints of the workpiece, the position for a hole to be drilled or acounterbore. For each drilling point in this embodiment one plate isrequired. The machine table 11 has a recess fitting the workpiece 12,and in it the workpiece is mounted. The workpiece is held down by a foot13, which has a bolt 13 which in turn is under the pressure of a spring14. In order to limit the longitudinal movement of the bolt 13 and tosecure it against turning, it is provided with a groove 13 into which ascrew 15 projects. Two locating pins 16 are fixed in the plate 6 andengage in the locating holes 12 in the workpiece, thereby connecting thecoordinate plate 6 to the workpiece 12.

A bush 17 of insulating material is pressed into a bore in the machineframe 1, into the bottom of which an adjusting screw 18 is screwed,which strikes against a bolt 20 carrying a contact carrier 19. The bolt20 is secured against turning by suitable means and drawn back againstthe adjusting screw 18. The contact carrier 19 carries a contact plate21, which is in contact with the adjusting nut 5 which carries theworking spindle 4 when the drill 22 applies no axial pressure, i. e.when no drilling is being done. The contact carrier 19 is connected byan electric conductor 23 to a control system (not shown).

Another bush 25 of insulating material, which is pressed into a bore inthe machine frame, has at the bottom an adjusting screw 26 screwed intoit. A contact carrier 27 is secured to a bolt 28, which is mounted to belongitudinally slidable in the bush 25 and is prevented from turning bymeans not shown. A spring (likewise not shown) urges the bolt 28 in thedirection of the adjusting screw 26. Above the top face of the bush 6the contact carrier 27 is furnished with a contact head 29, so that thebush 6 when pushed upwards strikes with its face against the contacthead 29.

The operation of this embodiment is as follows: The machine table 11with the workpiece 12 set in is brought by hand or mechanically into thedrilling position with an axial deviation of some hundredths of amillimetre. This must be done so accurately that the points of thelocating pins 16 dependably reach the locating holes in the workpiece12. The machine table 11 has thus assumed the position shown in dottedlines in Figure 1. The foot 13 is also in the position shown in dottedlines. The machine table 11 is then brought close to the machine frame 1or conversely in the axial direction to the working spindle 4. By movingthe machine table 11 near the machine frame 1, the foot 13 is first madeto press on the workpiece 12 through the action of the spring 14. Byfurther raising the machine table, the locating pins 16 are made topenetrate into the locating holes 12 in the workpiece, until the pinsbear on their shoulders. But before the locating pins can penetrate thelocating holes in the workpiece, the bush 6 must by constraint bealigned with the working spindle 4 to such an extent that the locatingpins coincide exactly with the holes. For this purpose the bush 6 withthe guide pins 7 is raised-until the latter are lifted off the surfacesof the grooves 8 which surfaces are disposed in wedge fashion inrelation to one another, and the bush 6 can freely swing out radiallyand the locating pins follow the locating holes. If the machine table,and hence also the bush 6 and the guide pins 7 are lifted further, thelatter press from below against the ring 10 acted on by the spring 9.The action of the spring 9, together with the dead weight of the bush 6,should press the locating pins 16 into the locating holes in theworkpiece as far as their shoulders.

If however the locating pins have not penetrated into the locating holesbecause of obstructions, such as cuttings or ridges on the workpiece,whereby the spring 9 woul be additionally compressed to the extent ofthe length of the locating pins, the bush 6 will be too high to theextent of the penetrating length of the locating pins, so that its topface makes contact with the contact head 29. At the moment when thelocating pins should have penetrated up to their shoulders into theworkpiece, an electric control current is passed from a source ofcurrent through a cut-off device (not shown), conductor 30, contactcarrier 27, and contact head 29. If at that moment that locating pinshave penetrated insufficiently or not at all into the locating holes,the face of the bush 6 will be in contact with the contact head 29 andwill thus close the circuit from the source of current through thecut-off device, conductor 30, contact carrier 27, contact head 29,frame, source of current, and the machine is cut off immediately.

In order to ensure the exact maintenance of the coordinates, it isadvisable, as shown in Figure 4, to cut a centre with a centre bit. Ifthe plate 6 is made accurately, the control device correctly adjusted bytheadjusting screw 26, and the abovementioned centre is cut, even thesmallest errors in the coordinates is impossible.

In order further to improve the invention, a control system is providedwhich stops the machine if a drill breaks, which would otherwise resultin defective workpieces. To this end the adjusting nut 5 mounted on theworking spindle 4 has axial clearance of a few hundredths of amillimetre between the contact plate 21 and the head 2 of the sleeve 2,this clearance being adjusted by the adjusting screw 18. On commencementof the drilling, the axial pressure produced by the drill 22 raises theworking spindle 4 with the adjusting nut 5, so that the latter is liftedoff the contact plate 21 and presses against the head 2 of the sleeve 2.At the moment when the adjusting nut 5 is no longer in contact with thecontact plate 21, so that the drill has already started to drill, acurrent impulse is passed from a source of current through the conductor23, contact carrier 19, and contact plate 21. If at that moment thedrill is in order, the circuit between the contact plate 21 and theadjusting nut 5 is broken. If however the drill has broken off or hasbeen pushed back in the clamp, the spindle 4 is not raised at the momentof the current impulse, but has dropped down, so that the adjusting nut5 is in contact with the contact plate 21 and closes the circuit fromthe source of current, through the cut-off device (not shown),

conductor 23, contact carrier 19, contact plate 21, adjusting nut 5,frame,- and back to the source of current. The cut-oft device isconsequently operated and the machine is stopped.

Figures 3 and 4 illustrate a modification. In the drilling table 32 aworkpiece 33 is partly let-in and is held by an intermediate bridge 34.A bolt 35 is pressed into this intermediate bridge and is provided witha head 35 against which a compression spring 36 acts, which thus pressesthe workpiece 33 against the drilling table by means of the intermediatebridge 34. The workpiece 33 is a solid round disc without holes. In therecess in the drilling table it has a clearance of some hundredths of amillimetre in diameter. The intermediate bridge also has a circularrecess in relation to the drilling table and larger than the latter, theaxis of said recess coinciding as far as possible with that of therecess in the drilling table 32. The surface of the recess in theintermediate bridge is longitudinally ribbed in order to secure theworkpiece better against rotation. The recess in the drilling table 32is an approximate guide for the workpiece 33, whilst that in theintermediate bridge is an absolutely accurate guide, since it isprovided with locating holes 37 and 37 The latter are intended to guidethe locating pins 38, which are pressed into the plate 39. The plate 39is made in one piece with the bush 39 and, like the bush 6 in Figure 1,can swing out a limited distance in any direction. The centre bit 40turning accurately in the axis of the bush 39 can thus be aligned withthe plate 39 and intermediate bridge 34, and cut a centre for guiding adrill at an accurately determined point in the workpiece 33.

Another modification is illustrated in Figures 5 and 6, which show how aform plate as workpiece can be drilled with drilling bushes. A workpiece42 is partly let into the drilling table'41, once again with clearance.The workpiece 42 already has a hole 43, in which a locating pin 44 isguided. A coordinate plate 45 is pressed fast on to a bolt 46 which isaxially slidable, is acted on axially in the downward direction byspring pressure, and is secured against turning. In addition to thelocating pin 44 pressed into the plate 45, the plate 45 is provided witha shaped part 47, which partly guides the workpiece against its surface.The workpiece is thus guided by the locating pin 44 and the shaped part47 of the plate 45. The latter has a drilling bush 48, through which thedrill 49 drills into the workpiece. In this embodiment the guiding ofthe working spindle is rigid, because the plate it also rigid. Onthe'other hand, however, the workpiece 42 is slidable to a limitedextent, so that it can be aligned by means of the plate 45.

Finally, the modification illustrated in Figures 7 and 8, which is alsoprovided with a rigidly guided working spindle, will also be brieflydiscussed. A stripper 52 serves to strip the workpiece 51 from thelocating pins 55. It is secured on a bolt 53, which under the action ofa spring (not shown) is urged to push the holder against the workpiece.A distance pin 54 holds the stripper 52 suspended above the workpiece,so that the latter can be freely aligned against the locating pins 55which are pressed into the plate 56. In the workpiece 51 a centre 57 hasalready'been cut in a previous operation by means of a centre bit, sothat the drill 58 is guided.

The mode of operation of the different embodiments correspondsapproximately to that in the case of devices in general use.

I claim:

1. In a drilling machine, in combination, a spindle adapted to carry adrill and having a journal portion; a bearing engaging said journalportion of said spindle to guide the latter for rotation; support meanssupporting said spindle and said bearing for movement in axial directionand for tilting movement so that the spindle axis may be oriented with agiven point; drive means operatively connected to said spindle forrotating the latter within said bearing without preventing the tiltingmovement of said spindle and bearing; and means connected directly tosaid bearing for automatically bringing during movement of said bearingin axial direction the axis of said spindle and a straight line passingthrough the workpiece into coincidence so that a drill carried by saidspindle will drill in the workpiece a hole having an axis coincidingwith the spindle axis and the straight line.

2. In a drilling machine, in combination, a spindle adapted to carry adrill and having a journal portion; a bearing engaging said journalportion of said spindle to guide the latter for rotation; support meanssupporting said spindle and said bearing for movement in axial directionand for tilting movement so that the spindle axis may be oriented with agiven point; drive means operatively connected to said spindle forrotating the latter within said bearing without preventing the tiltingmovement of said spindle and bearing; radial positioning means connecteddirectly to said bearing for automatically radially positioning duringmovement of said bearing in axial direction said bearing and spindlewith respect to a workpiece; and axial positioning means connected tosaid radial positioning means for axially positioning said bearing withrespect to a workpiece.

3. In a drilling machine, in combination, a spindle adapted to carry adrill and having a journal portion; a bearing engaging said journalportion of said spindle to guide the latter for rotation; support meanssupporting said spindle and said bearing for movement in axial directionand for tilting movement so that the spindle axis may be oriented with agiven point; drive means operatively connected to said spindle forrotating the latter within said bearing without preventing the tiltingmovement of said spindle and bearing; a flange fixed to and extendingradially outwardly from said bearing, said flange having a face which isdirected downwardly when said spindle and bearing extend substantiallyvertically with a drilled carried "by said spindle extending downwardlytherefrom; and a plurality of positioning pins respectively fixed tospaced portions of said flange, extending from said face thereof, andeach having an annular shoulder spaced from and directed away from saidface, all of said shoulders being located in a plane normal to thespindle axis.

4. In a drilling machine, in combination, a spindle adapted to carry adrill and having a journal portion; a bearing engaging said journalportion of said spindle to guide the latter for rotation; support meanssupporting said spindle and said bearing for movement in axial directionand for tilting movement so that the spindle axis may be oriented with agiven point; drive means operatively connected to said spindle forrotating the latter within said bearing without preventing the tiltingmovement of said spindle and bearing; a flange fixed to and extendingradially outwardly from said bearing, said flange having a face which isdirected downwardly when said spindle and bearing extend substantiallyvertically with a drill carried by said spindle extending downwardlytherefrom; a plurality of positioning pins respectively fixed to spacedportions of said flange, extending from said face thereof, and eachhaving an annular shoulder spaced from and directed away from said face,all of said shoulders being located in a plane normal to the spindleaxis; and spring means operatively connected to said bearing for urgingthe same toward a workpiece so that said pins may extend into openingsof a workpiece to bring a predetermined point of the workpiece and thespindle axis into coincidence and so that said shoulders may pressagainst the workpiece to position the bearing and workpiece axially withrespect to each other as well as to guarantee that the spindle axisextends normally through the workpiece.

References Cited in the file of this patent UNITED STATES PATENTS1,159,196 Eden Nov. 2, 3.915

1,814,920 Hartwell July 14, 1931 2,070,463 Allemann Feb. 9, 19372,625,062 Heil Jan. 13, 1953 FOREIGN PATENTS 802,768 Germany Feb. 22,1951

